State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China.
Ecol Lett. 2010 Mar;13(3):284-91. doi: 10.1111/j.1461-0248.2009.01421.x. Epub 2010 Jan 21.
Atmospheric CO(2) enrichment generally stimulates plant photosynthesis and nutrient uptake, modifying the local and global cycling of bioactive elements. Although nutrient cations affect the long-term productivity and carbon balance of terrestrial ecosystems, little is known about the effect of CO(2) enrichment on cation availability in soil. In this study, we present evidence for a novel mechanism of CO(2)-enhancement of cation release from soil in rice agricultural systems. Elevated CO(2) increased organic C allocation belowground and net H(+) excretion from roots, and stimulated root and microbial respiration, reducing soil redox potential and increasing Fe(2+) and Mn(2+) in soil solutions. Increased H(+), Fe(2+), and Mn(2+) promoted Ca(2+) and Mg(2+) release from soil cation exchange sites. These results indicate that over the short term, elevated CO(2) may stimulate cation release from soil and enhance plant growth. Over the long-term, however, CO(2)-induced cation release may facilitate cation losses and soil acidification, negatively feeding back to the productivity of terrestrial ecosystems.
大气 CO(2) 富集通常会刺激植物光合作用和养分吸收，改变生物活性元素的局部和全球循环。尽管营养阳离子会影响陆地生态系统的长期生产力和碳平衡，但人们对 CO(2) 富集如何影响土壤中阳离子的可用性知之甚少。在这项研究中，我们提供了证据表明，在水稻农业系统中，CO(2) 增强了土壤中阳离子释放的一种新机制。升高的 CO(2) 增加了地下有机 C 的分配和根的净 H(+)排泄，并刺激了根和微生物的呼吸作用，降低了土壤氧化还原电位，并增加了土壤溶液中的 Fe(2+)和 Mn(2+)。增加的 H(+)、Fe(2+)和 Mn(2+)促进了土壤阳离子交换位点上的 Ca(2+)和 Mg(2+)释放。这些结果表明，短期内，升高的 CO(2) 可能会刺激土壤中阳离子的释放并促进植物生长。然而，从长期来看，CO(2) 诱导的阳离子释放可能会促进阳离子的损失和土壤酸化，对陆地生态系统的生产力产生负面影响。
